1. Field of the Invention
The present invention relates to an apparatus for acquiring display content data of each document element constituting a document from a description within the document or outside the document to create an output image for image formation.
2. Description of the Related Art
Along with an increase the frequency of printing hypertext documents such as HTML, XML, and XHTML-print, many printers have been developed which can accommodate hypertext documents. For example, Japanese Patent Publication Laid-open No. Hei 11-134125 discloses a printer device for acquiring and printing a hypertext document and document element data which constitutes the document from each server on the Internet. The process in which a printer itself downloads and prints hypertext document data is also referred to as pull printing.
Japanese Patent Publication Laid-open No. 2001-101091 discloses a pull-print system in which, in response to a request from a printer to acquire a part of hypertext document data, a proxy server collectively acquires the entire data containing the requested portion of data from the Internet and provides only the requested portion of data to the printer.
In printing a hypertext document, the printer analyzes the document from its beginning and, when it finds a description of a source file name and so forth of data to be incorporated into an output, sends a file acquisition request to a server on the Internet. Then, the file provided in response to the request from the server is developed into a bit map for incorporation into an output image, which is then printed on a predetermined medium such as a sheet of paper.
Here, data of each document element constituting a hypertext document may generally be stored in two or more different servers on the Internet. Therefore, acquisition of all data generally takes some time. Moreover, because a period of time necessary for data acquisition may vary depending on a response time of each server, and so forth, data may not always be acquired in the order of sending acquisition requests to the Internet. Therefore, it may often be the case that data of an element to be incorporated into a subsequent page is acquired before that for a preceding page.
In printing, an earlier page must be output earlier in order. Even though data for a subsequent page is acquired earlier, the data must be held in a printer, waiting for all data for its preceding page to become available, as it cannot be output before its preceding page. Therefore, in conventional printers, generally, all necessary data in printing a hypertext document is collectively downloaded to the printer before initiation of printing. This requires a printer to incorporate a large capacity storage device in order to print a large hypertext document, which causes cost increase.
Japanese Patent Publication Laid-open No. 2001-101091 discloses a solution to this problem. Specifically, this application discloses a technique in which, while monitoring free capacity in a process buffer within a printer, an acquisition request is sent for a portion of downloading data which can be stored in the free portion every time some free capacity becomes available in a process buffer. With this arrangement, required process buffer capacity can be suppressed.
The technique of Japanese Patent Publication Laid-open No. 2001-101091, however, may cause a problem such that, although a data acquisition request is sent every time some free capacity is secured in a process buffer, the requested data may not be acquired immediately depending on the state of a server holding the data or the Internet, which may cause delay in the printing. This application proposes as a solution to this problem, provision of a proxy server within a LAN to which the printer is connected, for collective data acquisition from the Internet, so that data can be provided from the proxy server to the printer. This is indeed a very effective solution, but it also has the disadvantage that it requires a large-scale system structure.